Imagine the disappointment, you’ve taken your miniature out of the oven, cooled it down and you notice an air bubble in your design. Air bubbles in polymer clay are frustrating, but they aren’t inevitable. All you need is the right preparation to avoid them.
Air bubbles in polymer clay are caused by pockets of air being trapped in the clay. This can happen due to either:
- Moisture being caught in the clay and heating up to create steam when baked, which expands and creates and air pocket.
- Air being trapped in the clay during conditioning, this is most likely to happen with clay that’s too soft or if you’re repeatedly folding the clay and trapping air in it.
Now you know why it happens, you can find out ways to avoid it. Below, I’ve looked into the best ways to avoid getting air bubbles in polymer clay and what to do if you find a bubble after your clay has been baked.
How To Avoid Air Bubbles In Polymer Clay Caused By Trapped Moisture
Soft or sticky clay holds more moisture than firmer clay. When baked, the moisture in the clay will warm up and turn to steam, which can create little pockets of air in your model.
You can try these tips below to stop this from happening:
- Allow your model to sit for a while (say, a couple of hours) in a dry area before baking it so any moisture can escape or be reabsorbed by the clay.
- Keep the room you’re working in as cool and dry as possible.
- Keep your hands cool and dry by regularly wiping them or wearing gloves.
Polymer clay is more prone to bubbling if the clay is too soft or if it feels wet and sticky. You can reduce the moisture by leaching the clay between two pieces of paper for 24 hours. Simply sandwich the clay between two sheets of paper and two tiles. The tiles will add a little weight to gently squeeze the excess moisture out and also protect your surfaces from any oils that leach out.
Reducing the amount of moisture in your clay can help reduce bubbling. Moisture can come from a number of things:
- Humidity – if you’re working in a humid environment, it doesn’t matter if it’s hot or cold, if there’s humidity from either damp or heat it could cause bubbles.
- Your hands – our hands naturally release moisture which is transferred to the clay. An easy way to avoid this is to wear gloves!
- Embellishments – anything you add to your clay could also increase the moisture content. Materials such as paint, wood, glue or anything that’s not clay can all add moisture.
- Mould releases – if you use water as a mould release then you’ll need to leave your clay to dry out for a while once you’ve taken it out of the mould. This will help any excess moisture to be released before baking. Alternatively, you can wipe any excess water off the clay once you’ve released it from the mould.
- Condensation – popping your clay into the freezer for a few minutes is a great way to harden it up, but when you take it out you’ll need to wipe off any condensation.
How To Avoid Bubbles In Polymer Clay Caused By Conditioning
Avoid rolling out your clay flat and the folding it over when you condition it.
Instead, roll the polymer clay out into a sausage shape with your hands, fold it in half, roll it out into a sausage shape again and continue until your clay is fully conditioned.
Air bubbles are more likely to form if you’ve made a model out of clay that’s too hard and hasn’t been conditioned properly. However, if it’s too soft, bubbles are likely to form as well so it’s a balancing act!
If you prefer to use a pasta machine for conditioning your clay, then use it on the thickest setting. Rolling on a thin setting creates ripples that can catch air. When you’ve folded your clay over, don’t put it through the machine so the ‘open’ edge of the fold goes in first, this will force air into the folded edge of the clay, creating a pocket of air.
Ripping the sheet and placing the layers on top of each other before putting them through the machine will trap less air than folding the sheet when you’re conditioning it.
If you spot any air bubbles in your polymer clay as you’re conditioning it, then either pop them with a pin or press down on them gently with a finger until they pop.
The Brand Of Clay You Use Maybe More Prone To Air Bubbles
Sculpy III seams to be more prone to air bubbles than other brands, probably because the clay is softer so more air can make its way in.
Properly conditioning the clay is one of the best ways to get rid of air bubbles. If you have a brand of clay that’s prone to getting air bubbles, or if you’ve noticed them in your work before, then you should avoid using a pasta machine to condition your clay and instead use the sausage method described above.
Below, I did a few experiments to see which clay and method creates the least bubbles. In all the experiments I conditioned the clay in the same room, on the same surface, at the same temperature and humidity level and used gloved.
DATA TO FOLLOW!
| Brand of clay | Conditioning method | Number of bubbles |
How To Fix Air Bubbles In Baked Clay
Most issues with air bubbles arise at the conditioning and modelling stage, but if you’ve taken your model out of the oven and noticed air bubbles in it, all is not lost.
All you have to do is pop the bubbles with a pin and then gently sand the area until it’s smooth. If the bubble has left a hole that’s too big or too tricky an area to sand, you could repair the hole with some more clay or an embellishment.
Conclusion
After reading and watching everything I could online and doing my own experiments, I found that the best way to minimise bubbles in polymer clay is to keep the clay as dry as possible when working with it, not folding it during the conditioning process and letting it sit for a while before baking it.
Further Questions
Should I Leave My Clay Before Modelling With It To Help Reduce Bubbles?
Yes, clay is easier to handle and less likely to trap bubbles if it’s cooler, so once you’ve conditioned the clay, let it cool a little bit before making your model. Letting your clay rest for a while after modelling it can also help to reduce bubbles as they will have time to be reabsorbed into the clay.
Do Bubbles Happen In Polymer Clay Miniatures?
Bubbles are less of a problem when working with miniatures as you’re working with less clay. Even if you roll a larger sheet out, for example to make mini cookies with, you can just avoid any areas of clay with bubbles in them to model your creations.
Bubbles tend to be more of an issue with models that are a few centimetres large or more, this is probably because there’s more clay for the bubbles to get trapped in. So although it’s not a huge problem when making miniatures, it’s worth addressing if you want perfect results every time.